1. Field of the Invention
The present invention relates to a recording/reproducing apparatus for, and method of, recording/reproducing information signal by a write/read head into and from a recording medium having a plurality of data tracks.
2. Description of Related Art
Widely used conventional recording media such as flexible disc (will be referred to as xe2x80x9cdiscxe2x80x9d hereinunder) are those having, when formatted, a recording capacity of about 1.44 Megabytes (will be referred to as xe2x80x9csmall capacity discxe2x80x9d hereinunder). Such small capacity discs are played in conventional recording/reproducing apparatuses (will be referred to simply as xe2x80x9cdisc drivexe2x80x9d hereinunder) which are adapted to spin the disc at a speed of about 300 to 600 rpm for reading/writing information signal (will be referred to as xe2x80x9csmall capacity disc drivexe2x80x9d hereinunder).
The conventional small capacity disc drive comprises a magnetic head which is moved to a desired data track on a disc by a head moving means driven by a stepping motor. More particularly, the magnetic head is stepwise moved onto each desired data track radially of the disc by the stepping motor and information signal to write or read information signal n into or from the data track. The small capacity disc drive detects the position of a data track on which the magnetic head is positioned, from a number of pulses supplied to the stepping motor or an angle of rotation of the stepping motor.
On the other hand, there have been proposed discs having tracks formed narrower for a larger recording capacity and thus having a recording capacity as large as 150 to 650 Megabytes (will be referred to as xe2x80x9clarge capacity discxe2x80x9d hereinunder). For playing such large capacity discs, there have been proposed disc drives adapted to spin the disc at a speed of about 1,200 to 3,600 rpm for writing/reading information signal into and from the disc and thus attain an improved recording density and transfer rate (will be referred to as xe2x80x9clarge-capacity disc drivexe2x80x9d hereinunder).
Such a large-capacity disc stores positional information indicative of the position of each data track. The large-capacity disc drive detects the positional information to position a magnetic head thereof onto each desired data track. The Applicant of the present invention has proposed to use a voice coil motor as linear motor for moving the magnetic head steplessly radially of the disc to a desired data track on the disc.
The above large-capacity disc drive is also adapted to detect a positional information stored in the large capacity disc and apply tracking servo control for positioning the magnetic head onto a desired data track to write or read information signal into or from the disc.
For writing or reading information signal into or from a disc, the magnetic head is moved to a desired data track over other data tracks. To move to an adjoining data track, for example, the magnetic head is moved over a single data track. For moving to a desired data track over a plurality of data tracks, the move over single data track is repeated until the magnetic head arrives at the desired data track.
The magnetic head is moved over data tracks according to an external head move request signal or similar. Therefore, for moving the magnetic head over a plurality of data tracks to a desired data track, it is necessary in some cases to detect a plurality of external head move request signals coming correspondingly to the plurality of data tracks over which the magnetic is to be moved.
In this case, when a stepping motor is used to move the magnetic head over the data tracks, it is possible to complete the head move over the data tracks within a predetermined time even if the move over single data track is repeatedly done for the number of data tracks up to a desired data track. When a voice coil motor is used to move the magnetic head over the data tracks, however, the repetition of the move over single data track for the number of data tracks cannot complete the head move over the data tracks within a predetermined time as the case may be. When the magnetic head is moved by a voice coil motor to a desired data track on a small capacity disc, for example, since the disc has no positional information stored therein, it is necessary to confirm each of data track positions over which the magnetic head is being moved, possibly causing it impossible to complete the head move to the desired data track within a predetermined time.
Recently, a disc drive compatible with both the small capacity disc widely used and large capacity disc has been developed. However, when a disc drive having a magnetic head drive formed from the above-mentioned voice coil motor is used to play (write or read information signal into or from) both a large capacity disc and a small capacity disc, a problem will arise in some cases that the magnetic head cannot be moved to a desired data track on the small capacity disc within a predetermined time.
Also, some discs have no positional information stored therein, such as the above-mentioned small capacity ones. In this case, when a voice coil motor is used to move the magnetic head to a destination over data tracks, the present position of the magnetic head cannot be confirmed so that it is difficult to completely move the magnetic head to the desired data track within a predetermined time. When disc drive having the above voice coil motor as magnetic head drive is used to write or read information signal into or from each of a large capacity disc and small capacity disc, there will take place in some cases a problem that it is difficult to move the magnetic head to a desired data track on the small capacity disc.
Accordingly, the present invention has a primary object to overcome the above drawbacks of the prior art by providing a recording/reproducing apparatus and method adapted to positively move a write/read head to a desired data track over a single data track as well as over successive data tracks on a recording medium.
The present invention has a secondary object to overcome the above drawbacks of the prior art by providing a recording/reproducing apparatus and method adapted for use with a recording medium having no positional information stored therein, as well, and to move a write/read head with a high accuracy to a desired data track over a plurality of data tracks formed on such a recording medium.
The above object can be attained by providing a recording/reproducing apparatus comprising, according to the present invention:
a write/read head to write/read information signal with respect to a recording medium having a plurality of generally parallel data tracks formed thereon;
means for driving the write/read head in a direction perpendicular to the plurality of data tracks over the data tracks on the recording medium; and
means for controlling the head driving means according to a head move request signal to move the head to a desired data track;
the controlling means counting up a count of incoming head move request signals each time one head move request signal is supplied while counting down the count each time the write/read head is moved over one data track by the head driving means to provide a present count; and
the head driving means moving the head at a speed based on the present count.
The above object can also be achieved by providing a recording/reproducing apparatus comprising, according to the present invention:
a write/read head to write/read information signal with respect to a recording medium having a plurality of generally parallel data tracks formed thereon;
means for driving the write/read head in a direction perpendicular to the plurality of data tracks over the data tracks on the recording medium; and
means for controlling the head driving means according to a head move request signal to move the head to a desired data track;
the controlling means subtracting, from a count a of incoming head move request signals, a count b of data tracks over which the head is moved by the head driving means to provide a resulting count c=axe2x88x92b; and
the driving means moving the head at a speed based on the resulting count c.
The above object can also be attained by providing a recording/reproducing method in which a write/read head to write/read information signal with respect to a recording medium is moved to a desired data track on a recording medium according to a head move request signal, comprising, according to the present invention, the steps of:
counting up a count of incoming head move request signals each time one head move request signal is supplied while counting down the count each time the write/read head is moved over one data track by the head driving means to provide a present count; and
moving the head at a speed based on the present count.
The above object can also be attained by providing a recording/reproducing method in which a write/read head to write/read information signal with respect to a recording medium is moved to a desired data track on a recording medium according to a head move request signal, comprising, according to the present invention, the steps of:
subtracting, from a count a of incoming head move request signals, a count b of data tracks over which the head is moved by the head driving means to provide a resulting count c=axe2x88x92b; and
moving the head at a speed based on the resulting count c.
The above object can also be attained by providing a recording/reproducing apparatus comprising, according to the present invention:
a write/read head to write/read information signal with respect to a recording medium having a plurality of generally parallel data tracks formed thereon;
means for driving the write/read head in a direction perpendicular to the plurality of data tracks over the data tracks on the recording medium;
means for controlling the head driving means according to a head move request signal to move the head to a desired data track;
means for detecting a position of the head between two adjoining data tracks; and
means for controlling the moving speed of the head according to a speed information corresponding to the head position detected by the detecting means;
the head moving speed controlling means controlling the moving speed of the head to move the head to the desired data track.
The above object can also be attained by providing a recording/reproducing apparatus comprising, according to the present invention:
a write/read head to write/read information signal with respect to a recording medium having a plurality of generally parallel data tracks formed thereon;
means for driving the write/read head in a direction perpendicular to the plurality of data tracks over the data tracks on the recording medium;
means for controlling the head driving means according to a head move request signal to move the head to a desired data track;
means for detecting a moving speed of the head; and
means for controlling the moving speed of the head according to a result of comparison between a head speed detected by the head moving speed detecting means and a preset speed profile;
the head moving speed controlling means controlling the moving speed of the head to move the head to the desired data track.